Air activated heat technology, (sometimes referred to as flame-less heat technology or oxidative heat technology) is widely used to heat various products. The air-activated heater is contained in a package such that the heater can be used to heat various contents of a package, or contents in contact with the heater package. In addition the technology can be mechanically attached to thermoformable materials (for example formable splints and braces) to modify the shape using heat transfer. This technology is used in a variety of applications including as a method to heat combat rations, also known as a Meal, Ready to Eat (MRE). The technology is also used in connection with various cold weather activities and can be found in foot and hand warmer inserts as well therapeutic devices as across a variety of other uses.
The prior art method of using air activated heat technology is limited to restricting or increasing air flow by reducing or increasing the size of an outer (removable) barrier layer. Since uniform distribution of air is required for effective utilization of heat, reducing the access area is less effective and can cause hot spots and/or uneven heating.
In many applications where air activated heaters are used, problems arise based on the varying start temperatures. In the instance where air activated heaters are used to heat an MRE or a thermoformable splint or brace the starting temperature maybe be higher or lower than room temperature. For instance, a thermoformable splint used on a ski slope versus has a lower initial temperature than a splint used to help a soccer player on a hot soccer field. Current technology results in uneven heating, insufficient heating and/or burning or hot spots. Present technology does not allow for the same prepared package to be properly heated from varying start temperatures. The start temperature may or higher than intended based on available storage options. This is especially true for military uses of MREs since conditions may not allow for storage of MREs at or near room temperature. If an MRE package is prepared from a higher starting temperature than intended, when air is allowed to access the air activated heater the MRE will burn or otherwise over cook as the user has no control over, or option to reduce the air flow to the heater. Conversely, if an MRE intended to be kept at room temperature is used from a colder starting temperature, the air activated heater may not have enough air access to produce enough heat to fully warm or heat the contents of the package.